Portrait de Doina Precup

Doina Precup

Membre académique principal
Chaire en IA Canada-CIFAR
Professeure agrégée, McGill University, École d'informatique
Chef d'équipe de recherche, Google DeepMind
Sujets de recherche
Apprentissage automatique médical
Apprentissage par renforcement
Modèles probabilistes
Modélisation moléculaire
Raisonnement

Biographie

Doina Precup enseigne à l'Université McGill tout en menant des recherches fondamentales sur l'apprentissage par renforcement, notamment les applications de l'IA dans des domaines ayant des répercussions sociales, tels que les soins de santé. Elle s'intéresse à la prise de décision automatique dans des situations d'incertitude élevée.

Elle est membre de l'Institut canadien de recherches avancées (CIFAR) et de l'Association pour l'avancement de l'intelligence artificielle (AAAI), et dirige le bureau montréalais de DeepMind.

Ses spécialités sont les suivantes : intelligence artificielle, apprentissage machine, apprentissage par renforcement, raisonnement et planification sous incertitude, applications.

Étudiants actuels

Collaborateur·rice alumni - McGill
Co-superviseur⋅e :
Collaborateur·rice alumni - McGill
Doctorat - McGill
Superviseur⋅e principal⋅e :
Maîtrise recherche - McGill
Superviseur⋅e principal⋅e :
Maîtrise recherche - McGill
Co-superviseur⋅e :
Maîtrise recherche - McGill
Doctorat - McGill
Superviseur⋅e principal⋅e :
Maîtrise recherche - McGill
Collaborateur·rice alumni - McGill
Doctorat - McGill
Superviseur⋅e principal⋅e :
Maîtrise recherche - McGill
Maîtrise recherche - McGill
Superviseur⋅e principal⋅e :
Collaborateur·rice de recherche - McGill
Co-superviseur⋅e :
Stagiaire de recherche - McGill
Doctorat - McGill
Superviseur⋅e principal⋅e :
Stagiaire de recherche - McGill
Maîtrise recherche - McGill
Co-superviseur⋅e :
Doctorat - McGill
Superviseur⋅e principal⋅e :
Collaborateur·rice alumni - McGill
Co-superviseur⋅e :

Publications

Attention Option-Critic
A Brief Look at Generalization in Visual Meta-Reinforcement Learning
Due to the realization that deep reinforcement learning algorithms trained on high-dimensional tasks can strongly overfit to their training … (voir plus)environments, there have been several studies that investigated the generalization performance of these algorithms. However, there has been no similar study that evaluated the generalization performance of algorithms that were specifically designed for generalization, i.e. meta-reinforcement learning algorithms. In this paper, we assess the generalization performance of these algorithms by leveraging high-dimensional, procedurally generated environments. We find that these algorithms can display strong overfitting when they are evaluated on challenging tasks. We also observe that scalability to high-dimensional tasks with sparse rewards remains a significant problem among many of the current meta-reinforcement learning algorithms. With these results, we highlight the need for developing meta-reinforcement learning algorithms that can both generalize and scale.
SVRG for Policy Evaluation with Fewer Gradient Evaluations
Stochastic variance-reduced gradient (SVRG) is an optimization method originally designed for tackling machine learning problems with a fini… (voir plus)te sum structure. SVRG was later shown to work for policy evaluation, a problem in reinforcement learning in which one aims to estimate the value function of a given policy. SVRG makes use of gradient estimates at two scales. At the slower scale, SVRG computes a full gradient over the whole dataset, which could lead to prohibitive computation costs. In this work, we show that two variants of SVRG for policy evaluation could significantly diminish the number of gradient calculations while preserving a linear convergence speed. More importantly, our theoretical result implies that one does not need to use the entire dataset in every epoch of SVRG when it is applied to policy evaluation with linear function approximation. Our experiments demonstrate large computational savings provided by the proposed methods.
Learning to Prove from Synthetic Theorems
Eser Aygün
Vlad Firoiu
Laurent Orseau
Shibl Mourad
A major challenge in applying machine learning to automated theorem proving is the scarcity of training data, which is a key ingredient in t… (voir plus)raining successful deep learning models. To tackle this problem, we propose an approach that relies on training with synthetic theorems, generated from a set of axioms. We show that such theorems can be used to train an automated prover and that the learned prover transfers successfully to human-generated theorems. We demonstrate that a prover trained exclusively on synthetic theorems can solve a substantial fraction of problems in TPTP, a benchmark dataset that is used to compare state-of-the-art heuristic provers. Our approach outperforms a model trained on human-generated problems in most axiom sets, thereby showing the promise of using synthetic data for this task.
A Distributional Analysis of Sampling-Based Reinforcement Learning Algorithms
We present a distributional approach to theoretical analyses of reinforcement learning algorithms for constant step-sizes. We demonstrate it… (voir plus)s effectiveness by presenting simple and unified proofs of convergence for a variety of commonly-used methods. We show that value-based methods such as TD(
Efficient Planning under Partial Observability with Unnormalized Q Functions and Spectral Learning
Value Preserving State-Action Abstractions
David Abel
Nathan Umbanhowar
Dilip Arumugam
Michael L. Littman
Navigation Agents for the Visually Impaired: A Sidewalk Simulator and Experiments
Millions of blind and visually-impaired (BVI) people navigate urban environments every day, using smartphones for high-level path-planning a… (voir plus)nd white canes or guide dogs for local information. However, many BVI people still struggle to travel to new places. In our endeavor to create a navigation assistant for the BVI, we found that existing Reinforcement Learning (RL) environments were unsuitable for the task. This work introduces SEVN, a sidewalk simulation environment and a neural network-based approach to creating a navigation agent. SEVN contains panoramic images with labels for house numbers, doors, and street name signs, and formulations for several navigation tasks. We study the performance of an RL algorithm (PPO) in this setting. Our policy model fuses multi-modal observations in the form of variable resolution images, visible text, and simulated GPS data to navigate to a goal door. We hope that this dataset, simulator, and experimental results will provide a foundation for further research into the creation of agents that can assist members of the BVI community with outdoor navigation.
Option-Critic in Cooperative Multi-Agent Systems
Nadeem Ward
Maxime Chevalier-Boisvert
In this paper, we investigate learning temporal abstractions in cooperative multi-agent systems, using the options framework (Sutton et al, … (voir plus)1999). First, we address the planning problem for the decentralized POMDP represented by the multi-agent system, by introducing a \emph{common information approach}. We use the notion of \emph{common beliefs} and broadcasting to solve an equivalent centralized POMDP problem. Then, we propose the Distributed Option Critic (DOC) algorithm, which uses centralized option evaluation and decentralized intra-option improvement. We theoretically analyze the asymptotic convergence of DOC and build a new multi-agent environment to demonstrate its validity. Our experiments empirically show that DOC performs competitively against baselines and scales with the number of agents.
Algorithmic Improvements for Deep Reinforcement Learning applied to Interactive Fiction
Vishal Jain
William Fedus
Bellemare Marc-Emmanuel
Text-based games are a natural challenge domain for deep reinforcement learning algorithms. Their state and action spaces are combinatoriall… (voir plus)y large, their reward function is sparse, and they are partially observable: the agent is informed of the consequences of its actions through textual feedback. In this paper we emphasize this latter point and consider the design of a deep reinforcement learning agent that can play from feedback alone. Our design recognizes and takes advantage of the structural characteristics of text-based games. We first propose a contextualisation mechanism, based on accumulated reward, which simplifies the learning problem and mitigates partial observability. We then study different methods that rely on the notion that most actions are ineffectual in any given situation, following Zahavy et al.'s idea of an admissible action. We evaluate these techniques in a series of text-based games of increasing difficulty based on the TextWorld framework, as well as the iconic game Zork. Empirically, we find that these techniques improve the performance of a baseline deep reinforcement learning agent applied to text-based games.
Gifting in Multi-Agent Reinforcement Learning (Student Abstract)
This work performs a first study on multi-agent reinforcement learning with deliberate reward passing between agents. We empirically demonst… (voir plus)rate that such mechanics can greatly improve the learning progression in a resource appropriation setting and provide a preliminary discussion of the complex effects of gifting on the learning dynamics.
Options of Interest: Temporal Abstraction with Interest Functions
Temporal abstraction refers to the ability of an agent to use behaviours of controllers which act for a limited, variable amount of time. Th… (voir plus)e options framework describes such behaviours as consisting of a subset of states in which they can initiate, an internal policy and a stochastic termination condition. However, much of the subsequent work on option discovery has ignored the initiation set, because of difficulty in learning it from data. We provide a generalization of initiation sets suitable for general function approximation, by defining an interest function associated with an option. We derive a gradient-based learning algorithm for interest functions, leading to a new interest-option-critic architecture. We investigate how interest functions can be leveraged to learn interpretable and reusable temporal abstractions. We demonstrate the efficacy of the proposed approach through quantitative and qualitative results, in both discrete and continuous environments.